Reference to related documentation:
German 32 36 868 A1, Wallner et al.;
German 12 90 210, B.
The present invention relates to the technological field of wiring electrical apparatus or devices, for example luminaires, fluorescent light fixtures, or the like. The term xe2x80x9celectrical devicesxe2x80x9d also includes terminal blocks or terminal elements which may be associated with light sockets or the like, and which have at least one terminal, or may have a number of terminals, for example to provide connection points, test points, or support points for electrical wires. Specifically, the invention is directed to a method to wire the electrical terminals of electrical devices or systems, to a wiring apparatus to carry out the method, and to terminal constructions particularly suitable when the method is used.
U.S. Pat. No. 5,515,606, Albeck et al., assigned to the assignee of the present application, and the disclosure of which is hereby incorporated by reference, describes a method to wire electrical terminals of electrical devices, aggregates or assembled units or systems, which is particularly adapted to achieve high efficiency, reliable operation, and avoidance of erroneous wiring, or errors. The method can be used in general, but is especially suitable for wiring luminaires, especially fluorescent light fixtures, which have within the luminaire separate accessory apparatus, such as ballasts. The patent describes a method which permits complete automation of the wiring of such luminaires or, in general, electrical apparatus, aggregates, assemblies and systems. It permits elimination of preassembled, or precut lines, as well as wiring harnesses, since it permits direct association of the required wires with the device, or terminals the wires are to serve.
The method is carried out, by means of a position controlled mechanical wire placement element, hereinafter and for brevity, a wiring finger, in such a way that, first, the electrical device or system has terminal blocks or the like preassembled therein. The location of the fixture, as well as of the terminals, is fixed and determined in accordance with a positioning raster. By relative movement between the preassembled device, or system, and the wiring finger, a first connection terminal is brought in the operating region of the finger and is positioned with respect thereto in proper wire-laying orientation. The wiring finger then introduces one end of an electrical wire supplied, for example, from an external wiring supply, such as a supply spool, into a contacting zone of the first terminal. It is fixed in position at the same time when an electrical contact is effected. Further relative movement between the preassembled electrical device or system and the finger, along a predetermined path, results in positioning of the line, sequentially, to further terminals all within the operating range of the wiring finger, and properly oriented positioning of the finger relative to the next terminal. During this relative movement, the line is supplied to the finger with a suitable length corresponding to the line positioning path. The continuously supplied line is introduced, at any terminal, into a contacting zone. An electrical contact is made, and the position of the wire is fixed at the terminal. The wire may be cut or not; if not, a throughwired contact is made.
The line, which is so positioned, is cut at the final end in the region of the last terminal. The cut end of the line, as well as the terminal, are so constructed that the cut end is safely received in the terminal and protected against accidental contact. The line positioning element, that is for short, the finger, is so constructed that it has a positioning finger element projecting from a housing. A conductor duct is located within the finger element. A controlled feed for the wire is provided. The finger is controlled, for example, by an industrial robot, or automatic positioning system in accordance with a preprogrammed wiring path, which places the finger adjacent the respective terminal to be contacted. The contacting zone of the terminal is formed as a Slit Blade Insulation Piercing Connectorxe2x80x94hereinafter for short SBIPCxe2x80x94and the line which is to make contact at the terminal is pressed into the slit of the slit blade connector.
To place the wire into the SBIPC, a pressure element is provided movably secured on the finger and movable transverse to the axial orientation of the terminal end of a wire guide duct in the finger. The pressure element can be moved between two positions, one being a quiescent or rest position, remote from the terminal end of the wire duct, and the other a working position in which it projects over a line extending from the wire duct at one side, or at least is in approximate alignment with the upper side of the exit opening of the wire duct.
A separately controllable knife blade is located between the pressure element and the finger element as such, which cooperate with the opening surface of the wire exit opening of the wire duct, to permit cutting off the wire at the last terminal end when the positioning path of the wire has been run through.
The terminals are so constructed that they retain all the terminals within a contacting zone, and are surrounded within a housing of insulating material. The housing is formed with at least one introduction slot, open at an end, to receive the line, and further includes the SBIPC, which has its insulation piercing slit oriented to the introduction slot. The upper end of the slit is open. The SBIPC is retained in the insulating housing part in a manner to ensure that accidental contact therewith is not possible.
The housing, at least in one side thereof, and adjacent the introduction slot has an extension in form of a groove-like recess or depression, the width of which is larger than the width of the introduction slot, and the dimensions of which are so determined that a free end of a line which made contact to the SBIPC can be received in this slot, or groove-like extension. The slot or groove-like extension, as well as the housing, is generally matched to the dimensions of the wire-positioning finger and of the pressure element thereof, so that this extension can carry out a dual function:
(1) It receives a cut end of the wire at the last terminal of the wire positioning path in such a manner that it is safely retained against accidental contact. This means that the blank end of the wire cannot be reached from the outside in accordance with standard testing procedures, or at standard testing probe.
(2) The extension functions as a guide groove for the positioning finger of the positioning tool as the finger is moved over the terminal connection, and upon pressing the wire into the SBIPC by the pressure element.
The second function of the groove-like extension or depression at the terminal requires a predetermined minimum width of the depression which is substantially larger than the diameter of the wire, including its insulation. This is due to the size of the positioning finger which engages into the extension. The walls adjacent this extension duct or groove are thicker than the outer diameter of the wire insulation of the wire which is placed by the finger and located in the guide groove. This thickness dimension must also be extended to permit for slight shifting of the wire in the guide groove.
If multi-pole terminals are used, a terminal block will have a substantial width, due to the width of the slit or groove-like extension or depression of the housing at any one terminal, which is of substantially greater width than that of the wire, including insulation, itself. Some minimum dimension could not be decreased below that which is given by the width of the positioning finger and the required wall thicknesses, which are established in view of the air and surface creep path necessary for effective insulation between poles or terminals.
There are many applications where it is necessary, for example, due to space reasons, to closely move together terminals of a terminal block, or, otherwise, to make the individual terminals narrower than it was possible while retaining the groove-like depressions or extensions of the housing to permit the positioning finger to engage therein. In actual practice, it is desirable that such a device or assembly might have connection terminals of the well-known type which have grooves or extensions capable of receiving the width or thickness of the positioning finger, but which also have narrower connection points. If such narrower connection points, for space reasons, are also required, it was not possible to completely automatically wire a luminaire, or other device independently and without change in tools or wiring apparatus, in other words, to completely automate wiring of such devices or apparatus, entirely independently of the special construction of the terminals.
It is an object to improve the wiring method, the apparatus used therefor and terminals described above, which permits automatic wiring of terminal connections which are dimensioned without consideration of the dimensions of the positioning finger itself, but, rather, are dimensioned only with respect to the necessary insulation requirements, that is, the dimensions of air or creep paths to prevent spurious flashover.
Briefly, an initial terminal connection is established between a leading end of the wire and a terminal by
positioning the positioning elements of the finger spaced from the terminal, and in alignment with a terminal zone, for example above that side of the terminal;
a predetermined length of wire is fed from the positioning end of the finger over a pressure element which is so constructed that it will support and position the wire adjacent an outlet of a wire duct in the positioning finger at the side thereof remote from the contact zone. The finger end and the contact zone of the terminal are then moved towards each other, by causing relative movement, thereby pressing the wire by pressure of the pressure element into the SBIPC which is located in the contact zone, while maintaining the relative spatial position of the contact finger and the pressure element. The finger end is positioned outside of the contact zone itself and of adjacent portions of the insulated housing.
To establish a final wire connection between a trailing end of the wire and the terminal, the positioning end of the finger is positioned spaced from the final terminal, so that a portion of the wire adjacent the outlet of the wire duct in the finger end, at the side thereof remote from the contact zone of the terminal, will be supported by the pressure element; then, the finger and pressure element are moved towards each other, by causing relative movement. The pressure element, at one side, carries a knife which travels together with the pressure element, thereby cutting the wire close to the SBIPC. Immediately thereafter, by continued movement of the pressure element only, the wire is pressed into the SBIPC. The finger end, at all times, remains outside of the contact zone and the portions of the insulating housing surrounding the SBIPC.
The method, in accordance with the present invention, thus places the positioning finger, when making contact of the wire, outside of the outer dimensions of the connection terminal, that is, of the housing portions which retain the terminal element, the SBIPC, itself. The dimensions of the housing portion, thus, can be designed entirely independently on the size of the positioning finger, and with respect to insulation requirement matching only the standards, or requirements for the particular use, considering, of course, the necessary air and creep paths for safety. Reliable contact of the wire at the terminal is still ensured, without, however, requiring slowdown, or interference with automatic wiring. The method is also applicable for terminals which, in well-known manner, have slit or groove-like recesses or extensions designed to receive the contacting finger. If so, wiring can be carried out as customary, or in accordance with the above method, without making any changes in the apparatus or device, or in the wiring tools or system.
The wiring finger, in accordance with the present invention, is compact in construction and easily controlled. No additional programming or other measures are needed to control the movement by a standard industrial positioning system, robot, portal or gantry positioning arrangement. The wire is reliably pressed into the slit of the SBIPC. Guidance is provided by the pressure element, and hence by the wiring finger itself. If necessary, a pre-positioning of the wire, upon introduction of the wire into an inlet guide slot, is possible.
The terminal, as well as the terminal zones thereof, are, basically, similar to the terminals described in the referenced U.S. Pat. No. 5,515,606, Albeck et al. In contrast, however, this slot or groove-like extensions or recesses are, at least in part, so arranged that they have a width which is less, or only very slightly larger than the outer diameter of the wire including the insulation which is to be contacted by the SBIPC. Since wires and insulations are subject to dimensions and tolerances, xe2x80x9csmall or only slightly largerxe2x80x9d is intended to mean dimensions which correspond at least approximately to the standard or design dimension of the wire and its insulation. The dimensions of these slots or recesses, however, are independent of the dimensions of the positioning finger, and the spacing of terminals can be arranged to fit a predetermined raster. Thus, wall thicknesses, widths of contacts and the like can be decreased to such an extent that a terminal raster spacing of, for example, 3.5 mm is obtained. Specifically, it is possible to minimize the air and creep paths at least in the contacting zone and of the housing portions adjacent the slot and groove-like extensions only with respect to insulation requirements.
Various types of wiring positioning elements are described in the patent literature, see, for example, U.S. Pat. No. 3,930,524, German 12 90 210 B, and German 43 12 777 A1, to mention only a few examples. None of these wiring positioning elements can be used to carry out the present invention.
Terminals with contacting zones which include SBIPC""s are well-known in many constructions, one example being that described in German 32 36 868 A1, Wallner et al. The terminals provide protection against accidental touching of a cut wire end, but, overall, are so constructed that they do not fit into a raster, or are suitable for automatically position controlled wiring.
In accordance with a feature of the invention, the wire positioning element, that is, the wire positioning finger, has a pressure element with pressure surfaces located adjacent, or in close vicinity to the wire exit opening, or outlet, from wire being supplied by the finger, for example a duct, groove or the like. A cutter blade is movable together with the pressure element. The pressure element is movable with respect to the finger in at least three positions. In a first position, the pressure surfaces are spaced from the wire outlet to permit free wire feeding therefrom; in a second position, the pressure surface is essentially in alignment with the upper edge of the wire outlet opening; and in the third position, the pressure surface is in a position below the wire outlet opening, cutting the wire and pressing it into the SBIPC.
To carry out the method, and in dependence on whether a leading end of the wire is to be contacted, a through-connection is to be established, or the wire cut at a terminal or trailing end of a connector, the pressure element moves relative to the terminal independently of movement of the finger or the pressure element and the finger move together with respect to the terminal, i.e., retain their relative spatial alignment. Thus, the pressure element may be elevated and the finger as well; the pressure element and the finger can be lowered towards the terminal, or the pressure element can be raised together with the finger; or the pressure element can be lowered beyond the lower finger.
In accordance with another feature of the invention, the terminal is so constructed that it fits into a predetermined raster pattern, and the slit or groove-like extension of the housing beyond the region where the SBIPC is located has a width which is less, or only slightly greater than the outer diameter of the wire including the insulation which is to be contacted and retained in the SBIPC connector.